Lost turbotax 2018 tax infomation can I file turbotax 2019 electronically

Not having your 2018 tax file will not prevent you from being able to e-file 2019--unless you cannot figure out or know your 2018 AGI.  If you do not know the correct 2018 AGI then you will not be able to e-file 2019 successfully.

But what do you mean by "lost" 2018?  Did you forget how to access your online account, or did you have a hard drive crash?

Many people have multiple TT accounts and forget how to access them.  Log out of the account you are in now.

Account recovery

https://myturbotax.intuit.com/account-recovery/

https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password

Or did you use the desktop version of TurboTax?  If so, the files are on your own hard drive or any backup device you used like a flash drive.

https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have

https://ttlc.intuit.com/questions/1901535

https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac

https://ttlc.intuit.com/questions/1900721-find-your-tax-data-file-tax-file-in-windows

you can also go to the IRS website and get a transcript of your 2018 return which will have your AGI.  

without the TT 2018 file you will need to re-enter all your data including any items from 2018 that might affect 2019 such as carryovers.